Apparatus for removal of a certain number of plates from a stack of plates

ABSTRACT

A device for removing a desired number of plates from a stack of plates such as a stack of punched plates for making stators for electric motors. The stack is held in compression and a knife member is brought into contact with the side of a certain plate in the stack thus locating a desired number of plates between the knife and one end of the stack. Clamping means are provided adjacent the knife member to engage the stack such that when the compressive force holding the entire stack is removed, the portion of the stack between the clamping means and the one stack end is held in compression by the clamping means. In this manner, the desired number of plates are held stationary relative to the knife member and thus do not move relative to the knife member when the compressive force is removed. After separation of the other portion of the stack, the knife member and clamping means are disengaged from the portion of the stack containing the desired number of plates and a stack containing the desired number of plates is removed from the device.

United States Patent Kramer et al.

[54] APPARATUS FOR REMOVAL OF A CERTAIN NUMBER OF PLATES FROM A STACK OFPLATES [72] Inventors: Willi Kramer, Schlesienring 20, 6368 Bad Vilbel;Willi Muskulus, An der Pfaffenmauer 17, 6 Bergen Enkheim, Germany 22Filed: April 12,1971

21 Appl.No.: 132,998

[30] Foreign Application Priority Data April 24, 1970 Germany ..P 20 19924.0

Primary Examiner-Gerald M. Forlenza Assistant Examiner-George F. AbrahamAttorney-Larson, Taylor & Hinds Aug. 29, 1972 [57] ABSTRACT A device forremoving a desired number of plates from a stack of plates such as astack of punched plates for making stators for electric motors. Thestack is held in compression and a knife member is brought into contactwith the side of a certain plate in the stack thus locating a desirednumber of plates between the knife and one end of the stack. Clampingmeans are provided adjacent the knife member to engage the stack suchthat when the compressive force holding the entire stack is removed, theportion of the stack between the clamping means and the one stack end isheld in compression by the clamping means. In this manner, the desirednumber of plates are held stationary relative to the knife member andthus do not move relative to the knife member when the compressive forceis removed. After separation of the other portion of the stack, theknife member and clamping means are disengaged from the portion of thestack containing the desired number of plates and a stack containing thedesired number of plates is removed from the device.

9 Claims, 5 Drawing Figures PATENTEDA B m2 3 681.303

SHEET 1 BF 2 INVENTCRS WILL! KRAMER WILLI MUSKULUS (fi l a ATTORNEYSPATENTEDABBZQ I912 3.687; 303

SHEET 2 [IF 2 66 INVENTORS 72 42 42 WILLI KRAMER WILLI MUSKULUS Ozsvq, 37 4 ATTORNEYS APPARATUS FOR REMOVAL OF A CERTAIN NUMBER OF PLATES FROM ASTACK OF PLATES BACKGROUND OF THE INVENTION This invention relates to adevice for the removal of a certain number of sheets for example punchedplates for stators of electric motors, from a stack of plates compressedunder tension by division of said stack at a certain place by means of aknife member moveable from a position adjacent the side of the stack toa position in engagement with the side of the stack.

The technical problem in the case of such devices consists in graspingprecisely the same number of plates in each removing process. For thispurpose it is necessary to compress the plates stacked on top of oneanother under a relatively high pressure so that they will rest withcertainty closely one on top of the other without any space betweenthem. However, the strong compression of the stack of plates produces acertain elastic deformation of the plate material. When the compressiveforce is removed, the stack of plates expands to a thicknesscorresponding to the unloaded state and this urges the plates to moverelative to the knife member. However, the knife placed at the place ofdivision of the stack is not capable of resisting the 2 power of theelastic reshaping of the material. Expansion of the previouslycompressed sheet pack that is to be removed will therefore force one ormore plates past the knife while it is positioned in engagement with theside of the stack, and when the remainder of the stack is pulled awayfrom the place of division these one or more plates are not graspedalong with the others during the mechanical removal of the desiredstack. The result of the operation is therefore uneven.

It is an object of the present invention to provide a device of theinitially mentioned type which overcomes the disadvantages mentionedabove.

BRIEF SUMMARY OF THE INVENTION The foregoing and other objects whichwill be apparent to those having ordinary skill in the art are obtainedby providing an apparatus for removal of a desired number of sheets froma stack of sheets comprising a first sheet holding member, a secondsheet holding member spaced from said first plate holding member toaccomodate a stack of said sheets between said holding members, meansfor urging said holding members together to compress a stack of sheetspositioned between said holding members, a knife member located adjacentthe side of said stack of sheets intermediate said holding members, saidknife member being moveable between a first position spaced from theside of said stack of sheets and a second position in contact with theside of a certain sheet in said stack of sheets, means to move one ofsaid holding members away from the other holding member, clamping means,

for engaging the side of said stack of sheets, said clamping means beinglocated adjacent said knife member, and means for engaging said clampingmeans with the side of said stack of sheets whereby, upon movement ofone of said holding members away from the other holding member, theportion of said stack of sheets between said clamping means and saidother holding member is held there between under compression, and meansfor removing said portion of said stack of sheets from said apparatus toprovide a desired number of sheets from said stack of sheets.

The clamping means preferably includes jaws positioned adjacent theknife on the sides of the portion of the sheet pack that is to beremoved, between which jaws the sheets can be clamped in their positionassumed during compression of the stack so that they will maintain thisposition in the case of the release of the compressive force.

Through this invention, no more than the predetermined number of sheetswill be removed from the stack. Thus, the correct number of plates willnot be exceeded. This could happen in the event that one or more of theplates is caught by the last plate grasped by the knife. This mighthappen, for example because the ridges of cuts made by the knifeinterlock under the gripping pressure. In another case, the plates mightadhere to each other because of a poorly removed film of oil. Provisionshave been made in a preferred embodiment of the invention for a secondknife disposed with the intermediate distancing of one thickness of theplate measured at the edge of the knives, which second knife repels asheet adhering to the last plate grasped by the first knife.

In another embodiment of the invention, the two knives are pivotallymounted on axes extending transversely to the longitudinal axis of thestack of plates and are guided in opposite slanting positions crossed inthe manner of scissors, whereby the pivot axes are positioned in aclamping jaw which is radially movable in relation to the longitudinalaxis of the stack of plates.

DETAILED DESCRIPTION OF THE INVENTION There follows a detaileddescription of a preferred embodiment of the invention, together withaccompanying drawings. However, it is to be understood that the detaileddescription and accompanying drawings are provided solely for thepurpose of illustrating a preferred embodiment and that the invention iscapable of numerous modifications and variations apparent to thoseskilled in the art without departing from the spirit and scope of theinvention.

FIG. 1 is a diagrammatic side elevation view, partially in section, of adevice for the removal of a certain number of punched stator plates fromthe upper end of a perpendicular stack of plates;

FIGS. 2 (a), (b), (c), and (d) are diagrammatic views of a portion ofthe device of FIG. 1 showing a clamping means and knife members indifferent positions.

The device shown in FIG. 1 has a portal-like frame 10 in the open middleof which a power cylinder 12 is disposed. The latter can be operated,for example, hydraulically. The piston rod 14 of power cylinder 12 bearsat its upper end a holding plate or platen member 16 on which a stack ofplates 18, in this example punched plates for stators of electricmotors, has been placed. A certain number of plates is to be lifted offfrom supply stack 18 and is to be moved away for other processing, forexample, welding or screwing together, in one operating step. Theoperation is repeated successively and stack 18 is replenished asneeded.

The transportation of the sheet pack taken off at the upper end of stack18 is accomplished by means of an expanding mandril designated generallyas 20, which in its narrowest condition, fits into the center bore ofthe stator sheets and holds these whenever it is expanded. The expandingmandril 20 is seated firmly at an upper holding plate or platen member22, which in turn is connected with a bushing 24 which extends in thetransverse head of the frame toward the outside through an elongatedslit 26 extending perpendicularly to the plane of the drawing. A seriesof elongated holes 28 are disposed in the bushing 24. A bar 30 insertedinto said bushing 24 is attached with a certain axial play by means ofacross blot 32 extending through one of said holes 28 according to thechoice in several axial positions. Bar 30 at its upper end is attachedto a transfer car 34 which can be moved on rollers 36 along a rail 38 inthe direction of slit 26, that is perpendicular to the plane of thedrawing.

The expanding mandril 20, which, depending on the shape of the stackedplates, can be replaced by some other carrying elements, comprises apiston 40 (see FIG. 2 (d) with several encircling segments 42 which canbe expanded elastically and radially. The expansion may be accomplishedby means of an inside piston 46 which is conical at its front end andpresses against conical inside surfaces 44 of the peripheral segments42, which inside piston is moved by a double acting piston 50 cylinder48. Cylinder 48 can be acted upon hydraulically or pneumatically.

The sheets of stack 18 will be guided for motion in an axial directionalong a guide member 52. Whenever power cylinder 12 moves the lowerplaten 16' and the entire stack of plates upward, the uppermost platewill abut platen 22 which is supported by way of exchangeable stopelements 54 by frame 10. The level of the upper edge of the compressedstack 18 of the plates can be adjusted by the size of the stop elements54 and a corresponding selection of an elongated hole 28 in bar 30 forbolt 32.

On the side of the sheet pack opposite the guide member 52 there is amember moveably attached to the frame 10 generally designated by 56 andwhich contains a knife 58 which can be forced with its front edge 62laterally against the side of the sheet stack under the action of ahydraulic or pneumatic power cylinder 60.

In the compressed state of the stack of plates 18, whenever the plateslie tightly one on top of the other without any intervening spaces,there will be a number of sheets depending on the constant thickness ofthe sheets between platen 22 positioned by the stop elements 54, and theedge 62 of the knife. This number is the desired number of sheets to belifted from the stack. If now, as had been known hitherto, one forcesthe edge of the knife 62 against the side of the stack 18 in thecompressed state and if one afterwards lowers the lower platen 16, thenthe edge 62 of the knife is supposed to hold the sheets located betweensaid edge and the upper platen 22 while the sheets with the holdingplaten 16 located below the edge of the knife 62 are moved downwards.However, the knife 58 is not capable of absorbing the forces ofelasticity of the compressed sheet material without additional measures.If one would attempt to resist these forces nevertheless, it would benecessary to press the knife under very high pressure against thesheets, as a result of which the latter would be damaged. The attachmentof several knives distributed over the periphery of the stack of sheetswould first of all be very costly and in practice it would not lead tothe desired results either because one would have to count with the factthat in many instances all sheet elements are somewhat thicker on oneside than they are on the opposite side. These defects add up over theheight of the stack whenever the sheet elements are not turned betweenpunching and stacking. Several knives disposed in themselves on the samelevel may therefore grasp each time a different number of sheets.

In the case of the present device, the previously mentioned disadvantagewill be avoided by the fact that together with the knife 58, a clampingjaw member 64 is also pressed against the stack 18 of plates. This jawclamps the sheets just above the edge of knife 62 between itself and theguide 52 or of some other opposite clamping jaw, so that whenever thestack 18 of sheets is afterwards relieved of pressure, the sheets aboveknife 62 will maintain without change their position assumed in thecompressed state and the expansion of the entire sheet pack locatedabove the edge 62 of the knife will not press against the knife edge.

The pressure of the clamping jaw 64 and of the knife 58 need bemaintained only for a certain length of time until a sufficiently broadgap 66 (FIG. 2(d)) has developed between the firmly held upper sheetpack and the lower remnant of the stack 18 of sheets so that theperipheral segments 42 of the expanding mandril 20 can be spread out tograsp the upper sheets of the original stack of sheets. In thecompressed state of the sheets, the peripheral segments 42 will reachbelow the plane of the edge 62 of the knife to such an extent that,after separation of the upper sheet pack from the rest of the stack, thespreading apart of the peripheral segments 42, and the withdrawal of theclamping jaw 64 and of the knife 58, the sheets now carried by theexpanding mandril 20 can now relax and expand without pushing the lowestsheet from the peripheral segments 42. The removed sheet pack designatedin FIG. 2(d) as 68, hanging from the expanding mandril 20, is movedlaterally along the rail 38 for further processing.

In addition to the first mentioned knife 58, in the case of the deviceshown a second knife 70 is provided which has the task to import a pushto the sheet adhering below the sheet grasped by the edge 62 of theknife so that it will be lowered with the rest of the stack 18 of theplates designated in FIG. 2(d) as 72 and so that it will not be conveyedtogether with the sheets grasped by the expanding mandril 20 for furtherprocessing. The pushing off of the first sheet below that grasped by theedge of the knife 62 by way of the knife 70 can best be seen from FIG.2(c), where, however, the deformation of the sheet has been shown in anexaggerated way. The force exerted by the knife 70 on the sheet only inorder to push away the sheet, naturally does not need to be so greatthat the sheet will be deformed pennanantly.

Both knives 58 and 70 are held and guided diagonally with opposite slantcorresponding to their direction of thrust. Each of the knives ispivotally mounted on an axle 74, 76 which are each respectively attachedin slidable bearing blocks 78, 80. Both bearing blocks 78 and 80 areeach respectively guided in a milled out portions 82, 84 of the clampingjaw 64 and each is respectively forced toward the stack of plates by aspring 86, 88, inserted into the respective milled out portion.Therefore, both the clamping jaw 64 as well as both knives 58 and 70 aremoved toward the stack 18 of sheets by the power cylinder 60 via thepiston rod 90. In order that the bearing blocks 78 and 80 do not slipout from their milled out parts 82 and 84, lateral stops (not shown) areprovided. Also, guides for motion of clamping jaw 64 on frame have beenomitted for the sake of simplifying the drawing.

As shown in FIGS. 2(a) to (d), the knives 58 and 70 are disposedcrossing in the manner of scissors, whereby the knife 58 passes throughthe knife 70 which includes a channel 92. The front ends of the knifeare pressed by a leaf spring 94 one against the other and togetheragainst a lower stop surface 96 of the clamping jaw 64. In the retractedstarting position shown in FIG. 2(a), the intermediate distance of theedge 62 of the knife 58 from the thrusting edge 98 of the knife 70amounts to one thickness of a sheet. Whenever the knives as shown inFIGS. 2(b) to (d) thrust against the sheets, a torque directedoppositely in relation to the pertinent swiveling axle 74, 76 is exertedon each knife, which torque causes the edges 62 and 98 of the knives toseparate from one another under tension of the spring 94 upon thewidening of the gap 66 between the sheets.

In addition, FIG. 2(d) shows clearly that, quite apart from theadvantageous effect of the clamping jaw 64, the resilient, swivelablemounting of the knife 58 as provided does have the advantage that whilethe knife can be pressed against the stack of sheets relatively lightly,the contact pressure and thus the power of resistance which the knifeopposes to an expansion of the sheet pack 68 would rise considerablywhenever the lowest sheets of the pack 68 grasped by the edge 62 of theknife would attempt to press the knife 58 through its horizontal deadcenter position.

What is claimed is:

1. Apparatus for removal of a desired number of sheets from a stack ofsheets comprising:

a first sheet holding member;

a second sheet holding member spaced from said first sheet holdingmember to accomodate a stack of said sheets between said holdingmembers;

means for urging said holding members together to compress a stack ofsheets positioned between said holding members;

a knife member located adjacent the side of said stack of sheetsintermediate said holding members, said knife member being moveablebetween a first position spaced from the side of said stack of sheetsand a second position in contact with the side of a certain sheet insaid stack of sheets;

means to move one of said holding members away from the other holdingmember;

clamping means for engaging the side of said stack of sheets saidclamping means being located adjacent said knife member; and

means for engaging said clamping means with the side of said stack ofsheets whereby, upon movement of one of said holding members away fromthe other holding member, the portion of said stack of sheets betweensaid clamping means and said other holding member is held therebetweenunder compression; and

means for removing said portion of said stack of sheets from saidapparatus to provide a desired umber of sheets om said tack of he ts. 2.pparatus accor ing to clar m l further including a further knife memberadjacent said side of said stack of sheets, said further knife memberbeing moveable between a first position spaced from the side of saidstack of sheets and a second position in engagement with a side of afurther sheet in said stack of sheets, said further sheet being adjacentsaid certain sheet and located on the side thereof towards said oneholding member; said apparatus further including means for urging saidfurther knife member in a direction to separate said further sheet fromsaid certain sheet.

3. Apparatus according to claim 1 wherein said knife member is pivotallymounted about an axis directed transversely to the longitudinal axis ofsaid stack of sheets, said knife member slanting in a direction towardssaid other holding member.

4. Apparatus according to claim 3 wherein said knife member is held insaid slanting direction by stop means and a spring member urging saidknife member against said stop.

5. Apparatus according to claim 1 including means to urge said knifemember against the side of said certain sheet.

6. Apparatus according to claim 2 wherein said further knife member ispivotally mounted about an axis directed transversely to thelongitudinal axis of said stack of sheets, said further knife memberslanting in a direction towards said one holding member.

7. Apparatus according to claim 6 wherein oneof said knife membersincludes a channel through which the other of said knife members passes,said apparatus further including means urging one of said knife membersagainst the other knife member and further urging said other knifemember against a stop whereby the sheet-engaging edges of said knifemembers are positioned adjacent said stack of sheets and spaced apartabout one sheet thickness in a direction longitudinally of the stack ofsheets.

8. Apparatus according to claim 1 wherein said knife member is mountedon said clamping means.

9. Apparatus according to claim 7 wherein both of said knife members aremounted on said clamping means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTTGN Patent No. 303Dated August 29, 1972 lnventofls) Willi KRAMERand Willi MUSKULUS It iscertified that error appears in the aboveidentified patent and that saidLetters Patent are hereby corrected as shown below:

The heading should be amended to inc lude the. assignee as follows:

' j i Balze'T G Droll KG, Niederdorf e ldejn s Germany.

Signed and sealed this 1st day of May 1973.

(SEAL) Attest:

'ORM PO-1050 (10-69) USCOMM-DC 60376-P69 U.S. GOVERNMENT PRINTINGOFFICE: I969 0-366-334,

1. Apparatus for removal of a desired number of sheets from a stack ofsheets comprising: a first sheet holding member; a second sheet holdingmember spaced from said first sheet holding member to accomodate a stackof said sheets between said holding members; means for urging saidholding members together to compress a stack of sheets positionedbetween said holding members; a knife member located adjacent the sideof said stack of sheets intermediate said holding members, said knifemember being moveable between a first position spaced from the side ofsaid stack of sheets and a second position in contact with the side of acertain sheet in said stack of sheets; means to move one of said holdingmembers away from the other holding member; clamping means for engagingthe side of said stack of sheets said clamping means being locatedadjacent said knife member; and means for engaging said clamping meanswith the side of said stack of sheets whereby, upon movement of one ofsaid holding members away from the other holding member, the portion ofsaid stack of sheets between said clamping means and said other holdingmember is held therebetween under compression; and means for removingsaid portion of said stack of sheets from said apparatus to provide adesired number of sheets from said stack of sheets.
 2. Apparatusaccording to claim 1 further including a further knife member adjacentsaid side of said stack of sheets, said further knife member beingmoveable between a first position spaced from the side of said stack ofsheets and a second position in engagement with a side of a furthersheet in said stack of sheets, said further sheet being adjacent saidcertain sheet and located on the side thereof towards said one holdingmember; said apparatus further including means for urging said furtherknife member in a direction to separate said further sheet from saidcertain sheet.
 3. Apparatus according to claim 1 wherein said knifemember is pivotally mounted about an axis directed transversely to thelongitudinal axis of said stack of sheets, said knife member slanting ina direction towards said other holding member.
 4. Apparatus according toclaim 3 wherein said knife member is held in said slanting direction bystop means and a spring member urging said knife member against saidstop.
 5. Apparatus according to claim 1 including means to urge saidknife member against the side of said certain sheet.
 6. Apparatusaccording to claim 2 wherein said further knife member is pivotallymounted about an axis directed transversely to the longitudinal axis ofsaid stack of sheets, said further knife member slanting in a directiontowards said one holding member.
 7. Apparatus according to claim 6wherein one of said knife members includes a channel through which theother of said knife members passes, said apparatus further includingmeans urging one of said knife members against the other knife memberand further urging said other knife member against a stop whereby thesheeT-engaging edges of said knife members are positioned adjacent saidstack of sheets and spaced apart about one sheet thickness in adirection longitudinally of the stack of sheets.
 8. Apparatus accordingto claim 1 wherein said knife member is mounted on said clamping means.9. Apparatus according to claim 7 wherein both of said knife members aremounted on said clamping means.